Electric furnace workpiece ejector mechanism



Oct. 18, 1949. H. A. sTRlcKLAND, JR

ELECTRIC FURNACE WORKPIECE EJECTOR MECHANISM Filed Jan. 10, 1946 HAROLDAST-RICKLAND, JR

. A TTORNE Y Patented Oct. 18, 1949 ELECTRIC FURNACE WORKPIECE EJECTORMECHANISM Harold A. Strickland, Jr., Detroit, Mich., assigner, jby mesneassignments, to The Ohio Crankshaft Company, Cleveland, Chio, acorporation of Ohio Application January 10, 1946, Serial No. 640,229V

5 Claims.

This invention relates to ejector equipment, having particular utilityas'applied to induction furnace chambers. y

Ininduction furnaces the heating chamber is usually formed by aAcylindrical coil dening a tubular interior within which the workpieceis positioned for heating through inductive action. The inlet or mouthend of the furnace is at one end of the coil o-fsuch a furnace the otherend may be open for insertion of mechanism as desired. Insertion of theworkpiece is usually by manual means through the mouth-piece, the samebeing placed fully within bothends of the coil so that the inductiveaction may be uniform. In this position theworkpiece may not be easilygrasped for removal by tongs or the like applied at the inlet end.

One of the primary'objects of the present invention is to provideejector mechanism which by simple mechanical manipulation may be made toforce out the heated workpiece from the heating chamber of the furnaceto a point where the operator by means of tongs or other devices mayreadily grasp the same and remove it bodily from the chamber. Anotherobject of the invention is to provide such a push-out mechanism as maybe readily utilized in conjunction with tubular work-pieces, forexample, shells. Still another object is to provide a push-out deviceusable in connection with tubular work-pieces which in its structuretends to prevent substantial heating therein resulting in injury to thedevice and improper and undesired absorption of energy. An object alsois to provide a push-out device which lends itself without anymani-pulation to a disruption of current flow in its structure duringthe period of heating by the furnace, but which automatically whensubjected to pressure in the push out operation adjusts itself to aplural contact upon theworkpiece, thus facilitating easy removal of the`workpiece and properly balancing the `load on the push-out device. Anobject of importance in conjunction with the apparatus also is theemployment of magnetic units inl order to divert the liux flow from thepush-out device and thus aid in preventing undue heating thereof. Anassociated object is the provision of iiux diverting means which is notonly protective to the push-out device itself, but also aids inmodifying the heating effect along the workpiece as desired. Anotherobject related to the use of the mechanism is the employment of meansfor protecting the support of the push-outl device so that `even thoughthe support may be contained `in part within `the furnace interior end,

2 walls, the action of the inductiondoes notfunduly overheat the samebringing about a malformation of the Vsupporting structure whensubjected to load impact while in aA heated condition. Other objects oftheinvention will be apparent on consideration of a form ofthe inventionwhich may be preferred hereinafter described and .i1- lustrated intheaccompanying drawing-,-in which:

Figure 1 is a side elevation partly in sectionof a portion of a furnaceillustrating the placement and mode of operation of the push-outmechanism;

Figure 2 is a section through the push-out rod and support takenalonglines 2-2 `of Figure 1, illustrating the split support tube andthe`mode of application of the T-bar to the workpiece; and

Figure 3 is.anenlargedfragmentary sectional View showing the push-outmechanism of Figure 1 in greater detail.

In my copending application SerialNo. 384,503, filed March 2l, 1941,Electric furnace machine, now Patent No. 2,408,350, issued September 24,1946, I have illustrated and describedmechanism of the general typeherein-disclosed butapplicable primarily to a solid rod or barpositioned as a load within an induction coil. While the structure ofthis prior application is useful under certain conditions of use, .thereis a tendency for the rod end of the push-out device to becomeoverheated and to flare outwardly due to impact of the load when beingpushed into position. Also, the supporting tube or stock-gauge, as it iscalled, is also liable to overheatingand as a resulttends to mushroomthrough load impact thus destroying thel usefulness of the device. 'Ihestructure of the herein described mechanism tends to overcome thesedeficiencies by preventing undue development of eddy currents in thepush-rod end, and also yby slotting the end of the support tubediminishes the eddy current flow in the supporting tube itself.

Referring to Figure l of the drawing, there is disclosed a section of aninduction furnace including a support plate I to the ends of which isattached a casing having a front face 3 and a rear face 4. The frontface of the casing is apertured to receive a mouthpiece plate 5. Thismouthpiece is centrally apertured and provided with inwardly extendingfingers 6 which are spaced from each other and converge to define aninlet opening for the guidance of workpeces into the chamber of thefurnace. The induction coil unit of thefurnace'is set up in`prolongation of the mouthpiece opening, being shown as mounted uponI-bars T and 8 resting on the base I and adjustably secured by C-clamps9 and III which in turn rest on the I-bars l and 8. The C-clamps areprovided with adjustable devices II and I2 which are preferablyyieldable so that a firm grip of these holding devices-there being threeprovided--is secured.

The induction heating unit itself is a coil of tubular conductor I5preferably rectangular in cross-section, insulated on its outer surfaceby heat-resistant material such as Transite and on its inside byinsulating tubing I6 andan inner layer of firebrick I1. Embedded in therebrick as a cylindrical grill is a plurality of hollow tubes or railsaxially extending and provided with load bearing plates I8 forsupporting the load I9, which in the present instance is a pipe orshell. This grill is fixedly secured in direct alignment with the inletopening of the mouthpiece 5 so that when the workpiece is insertedthrough the mouthpiece it enters the heating chamber of the coil and maybe pushed completely therein.

The push-out mechanism generally indicated by the numeral is placedadjacent the end of the heating unit opposite from the mouthpiece, thatis, on the rear side of the furnace. The mechanism includes a supportingbracket 2I bolted to the rear casing plate and adapted to receiveadjustably the push-out rod support 22. This support is tubular andmovable for adjustment not only in the bracket 2|, but through anaperture formed in the casing plate, so that from a point exterior tothe casing the support tubing may be axially adjusted. Alternatively,this support is frequently referred to as a stock-gauge in that itgauges the extent of inner movement of the stock or workpiece inside thefurnace. Inasmuch as the stock-gauge has a limiting function for theworkpiece, it is preferably slotted for a short distance at the furnaceend, as indicated by the numeral 23, for a purpose hereinafter to bedescribed.

The push-out rod 24 is slidably movable in the direction of its axiswithin the support tube 22. This rod is of extended length and isprovided adjacent its outer end outside of the casing with an adjustablecollar 25. Supported also on the rear casing are brackets 26 and 21, oneabove the other, the bracket supporting a hydraulic motor 28 having amovable piston 29 adapted to have pivotal attachment at its end to alever arm 30 pivoted at 3| for movement thereof. The lever arm 30 isxedly connected to a second lever arm 32 which at its free end isengageable with the collar 25 on the push-out rod so that when uidpressure is exerted within the motor bringing about outward movement ofthe reciprocatable member 29, the pivoted lever 383--32 rotates on thepivot 3| `to cause movement of the collar 25 and attached rod 24 towardthe furnace. A spring 33 tends to return the extensible member 29 of themotor, as well as the arm 32 0f the lever, to inoperative position,permitting unrestrained outward movement of the push-out rod 24.Hydraulic pressure is applied to the motor-through the tubing 34 ascontrolled by the valve 35 which may be either adjacent the casing or ata point displaced therefrom as, for example, in front of the casingwhere it may be easily accessible to the operator.

The inner end of the push-out rod 24, that is, the end movable into thefurnace chamber, is fitted with a cross bar which preferably istransverse to the rod. The function of this cross bar is to engage atits ends the end of the tubing, such as a shell. which may constitutethe workpiece of the furnace so that when the push-out rod ismanipulated to move inwardly from the rear, by such engagement the shellis moved outwardly to a point where it may be completely removed by theoperator. It is pointed out that this cross bar, while it extends oneither side of the push-out rod to points adjacent the shell end, makescontact only at point 4I in the normal heating position of theworkpiece, whereas at the point 42 there is a physical disconnectionbetween the cross bar end and the shell end. The purpose of thisconstruction is to insure that during the heating operation there is noshort circuiting of the metal constituting the cross bar and shellresulting in an undue heating of the bar with deleterious effects.However, it is also desirable that during the actual push-out of theworkpiece there should be contact on opposite sides of the shell inorder to insure balanced pressure against the workpiece. This isaccomplished by the structure as shown, utilizing for the cross barmetal of such dimensions and substance that the yield under pressurepermits contact at the top as well as the bottom of the bar. The degreeof yield need be but small since the only requirement as regards the gapat the point of disconnection at the top of the bar, as shown in Figure1, is that there be no actual conduction of current.

There is also provided to add further protection to the cross bar in theprevention of undue heating thereof an accessory unit generallyindicated by the numeral 45. This unit consists of a plurality ofradially extending laminated plates of usual transformer iron-containingcomposition. This laminated unit is attached to the push-out rod 24 inany effective manner and serves for the purpose of diverting the flow offlux which normally passes through the shell interior in such a mannerthat less density of ux develops in the cross bar 40 than would be thecase if the unit were absent. This unit is preferably adjustable as toits point of attachment on the push-out rod so that the point ofgreatest effectiveness may be found at which the unit is permanentlyheld. It is pointed out in connection with this unit that its action indiverting flux may be useful also at displaced points along the interiorof the workpiece in that the density of ux in the workpiece itself maybe modified and consequently the heating effect. Where it is desiredthat different degrees of hardness, for example, be imparted to a shellby properly spacing flux-diverting units as that illustrated at 4'5,such a result may be brought about through a diversity in the heating ofthe shell from point to point. These various units may be all secured tothe push-out rod as a convenient means of support.

Summarizing the operation, the workpiece is inserted through themouthpiece and forced to the rear limit of the furnace chamber engagingthe cross bar 40 of the push-out mechanism and moving it to the rearpoint until it contacts with the stock-gauge 22. At this point thecollar 25 of the rear end of the push-out rod is in engagement with thelever arm 32 of the operating mechanism. The heating cycle is commencedand the shell brought up to temperature. During this heating theelectromagnetic energy is effective not only on the shell, but on thecross bar 40 as well as upon the end of the stock-gauge 22. However, byreason of the slotted end of the stock-gauge the circuital currents inthe stockgauge are effectively diminished, and as regards the cross bar,the contact of the same with the workpiece at only one point iseffective in conjunction with the diverting action of the laminated unit45 to very substantially reduce the heating effect of the magnetic flux.On the completion of the cycle the operator manipulates the valve means35 bringing about activation of the motor and an inward movementof thepush-out rod 24, both ends of the cross bar 40 engaging the workpieceand forcing the same outwardly through the mouthpiece to the point ofrod engagement by the operator.

The apparatus as described is preferred, but of course there may bemodifications. For example, the motor is described as the hydraulictype; other types maybe used. Also, the apparatus has been specificallyrelated to an induction furnace. However, we believe the apparatus maybe successfully applied to the other units wherein it is desired toprovide ready means for removal of a tubular load normally subject tomagnetic flux. Other modifications may be made such as may come withinthe scope of the appended claims.

What is claimed is:

1. In electrical furnace equipment, an induction coil having a chamberadapted to receive a generally cylindrical workpiece, a recprocatablerod movable in said chamber in alignment With the workpiece, aworkpiece-engageable element forming the chamber end of the rod, andmeans for reciprocating said rod to shift the workpiece outwardly fromsaid chamber, said element comprising a member with at least twobranches extending angularly from said rod engageable with the workpiecefor ejection thereof with one branch nominally extending into thechamber beyond the other branch.

2. A push-out rod for tubular workpiece subject to inductiveelectromagnetic iiux and contained in a tubular furnace, comprising anelongated member, means fcr supporting said member for axial movementinto and out of said furnace, plural `workpiece engaging elements xed tothe end of the member adjacent the furnace, one only of said elementsbeing normally in metallic electrical conductive relationship with theworkpiece during the heating cycle, the other of said elements normallymoving into contact with said workpiece on the application of pressureon the member to force the workpiece out of said chamber.

3. A push-out rod mechanism for tubular workpieces subject to magneticiiux and contained in a tubular electric induction furnace, comprising apush-out rod, means for supporting said rod for axial movement into andout of said furnace, a

workpiece engaging member fixed to Said rod for p engagement ywith theworkpiece, means for moving the rod and member toward said workpiece,and means for reducing the ux density effective in said member duringthe time of power application to said furnace.

4. A push-out rod mechanism for tubular workpieces subject to magneticflux and contained in a tubular furnace, comprising a push-out rod,means for supporting said rod for axial movement into and out of saidfurnace, a workpiece engaging member fixed to said ro-d engageable withsaid support and workpiece, and separate means for reducing the fluxdensity in said support and said member during the time of powerapplication to said furnace.

5. In an induction furnace, a tubular conductor coil forming a furnacechamber adapted to receive a tubular workpiece, a rod normallypositioned along the coil axis, a support for said rod, means for movingthe rod axially of the coil, workpiece engaging means secured to the rodfor engagement with, and movement of, a tubular workpiece, and meansmounted on Said rod for modifying the flux density of the coil effectivein said contact means and workpiece.

HAROLD Ai. STRICIUJAND, JR.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,367,124 Colby Feb. 1, 19211,862,120 Northrup June 7, 1932 2,182,341 Hulster Dec. 5, 1939 2,257,580Trompeter Sept. 30, 1941 2,337,258 Limpel Dec. 21, 1943 2,363,724 FordNov. 28, 1944 2,371,066 Richter Mar. 6, 1945 FOREIGN PATENTS NumberCountry Date 583,460 France Oct. 31, 1924

